The present invention relates generally to fluid control valves for production well equipment. In particular, this invention relates to back pressure valves for reverse cementing applications.
Production wells typically have valves and valve seats also known as check valves and back pressure valves. These valves are utilized in different applications in various industries including but not limited to the oil and gas industry. Current back pressure valves supply a one direction flow and a negative flow from the other direction. This may be desirable when a controlled flow is important for such purposes as safety well control while placing a casing string and/or tubing in a potentially active well.
Typical valves may be mechanically manipulated to selectively change the direction of flow during operations and then selectively change the flow direction back to an original direction. Valves are usually manipulated between configurations by mechanical movement of the casing/tubing, or placing an inter string inside the casing/tubing string to apply weight on the valve so as to hold the valve in an open configuration. Other mechanisms for manipulating valves include disabling the valve with a pressure activated ball or plug allowing flow to enter the casing/tubing string. But these valves cannot be reactivated, if desired. Other valves are manipulated when the casing bottoms in the rat hole at the bottom of the well bore so that the valve is mechanically held open by the set down weight.